Chennai: Dr Y. E. A. Raj, deputy director general of meteorology, Regional MeteoÂrolÂogical Centre, ChenÂnÂai, stated here on TuÂeÂsÂdÂay that major low pressure systems usually hit Tamil Nadu in December and so the state can expect more activity this month.
“Cyclonic storms form closer to the equator during December and so Tamil Nadu will receive more rainfall. The Helen system (November 19-23) was a somewhat unusual as it formed at a higher latitude,” he added.
With three cyclones, Phailin, Helen and Lehar, hitting the east coast this northeast monsoon, the low-pressure systems have been very active in 2013. Weathermen expect cyclones to hit Tamil Nadu in December, as the usual pattern of system formation takes place from the north to the south.
Cyclone systems form mainly nearer the northeast in October and slowly move towards the south as the year comes to a close. But the Helen cyclone that hit Andhra Pradesh in November was a rare case as it formed unusually at a slightly higher latitude.
“This year we have seen continuous cyclonic activity. Apart from the three cyclones that made landfall in Orissa and Andhra Pradesh (twice), Tamil Nadu witnessed one deep depression which made landfall near Nagapattinam on November 16.
It brought heavy rainfall to many parts of the state. But all the three cyclonic systems moved in the wrong direction and did not bring much rains to the state,” said Dr Y. E. A. Raj.
Weather blogger R. Pradeep John said that no one expected the Helen system to intensify into a cyclone as it formed at higher latitude. “But due to favourable sea temperature and no wind shear, the system got super intensified,” he added.
The Lehar system (November 23-28) was just the opposite of Helen, as the super intensified system was affected due to high wind shear and the cyclone dissipated within three to four hours of landfall.
The biggest among the three systems was cyclone Phailin (October 8-14) which had a reasonably high intensity while crossing land near Gopalpur in Odisha. “At one stage the Phailin system touched 200 kmph speed. It was a very severe cyclone,” said Dr Raj.
